河口蟹半峰在南太平洋沿岸分布范围很广(从20°S到53S°)。这种十足动物在这些沿海和河口栖息地中含量丰富,并作为斯努克鱼(Eleginopsmaclovinus)和海带海鸥(Larusdominicanus)的猎物发挥着关键的生态作用。它的饮食包括碎屑,死鱼,和甲壳类动物,和大型藻类Ulvasp。为了应对智利沿海不同的环境条件和人为影响,H.screnulatus可能在其生殖性状和胚胎元素组成上呈现种内变异,直接影响其生物适应性。沿着智利海岸,在智利的六个地区(北部:Tongoy(30°S);中南部:Lenga(36°S),分别于2019年春末和2020年夏初(从2019年11月至2020年2月)收集了女性个体,Tubul(37°S);南南方:Calbuco(41°S),Castro(42°S),奎隆(南纬43°)。环境条件(即海面温度,还记录了每个采样事件期间存在的降水和叶绿素α)。我们评估了雌性的生殖参数(繁殖力,生殖产量(RO))以及它们的体型(甲壳宽度和干重),volume,含水量,干重,元素组成(碳,氢气,氮:CHN),最后是他们胚胎的能量含量。我们的结果表明,海水温度的环境条件,降水(水盐度的代表)和叶绿素α(食物供应的代表)对雌性的生殖参数及其胚胎的特征有直接影响。我们在Calbuco和Quellón观察到低繁殖力和高RO,其中沉淀高(即稀释的盐度)并且温度和生产率低。对于胚胎特征,在河口地区的雌蟹中观察到体积和含水量的最高值(即Tongoy,Lenga,Tubul),值远高于智利内海中发现的值(即Calbuco,卡斯特罗,Quellón).对于元素组成,我们观察到来自Lenga(富氮地区)的雌性蟹的胚胎中的氮水平很高,C:N比例很低。各地之间波动的环境变量被证明可以调节H.scrnulatus的雌性和胚胎的种内变异,揭示不同的生殖策略,特别是在每个胚胎的质量和能量投资方面,随后影响了成功的胚胎发生和幼虫存活。
The estuarine crab Hemigrapsus crenulatus has a wide distribution range along the coast of the South Pacific Ocean (from 20 °S to 53 S°). This decapod is abundant in these coastal and estuarine habitats and plays a key ecological role as prey of the snook fish (Eleginops maclovinus) and kelp gull (Larus dominicanus). Its diet consists of detritus, dead fish, and crustaceans, and the macroalgae Ulva sp. In response to contrasting environmental conditions and anthropogenic impacts along the Chilean coast, H. crenulatus may present intraspecific variations in its reproductive traits and changes in the elemental composition of its embryos, directly affecting its biological fitness. Along the Chilean coast, female individuals were collected during late spring 2019 and early summer 2020 (from November 2019 to February 2020) in six areas of Chile (north: Tongoy (30°S); south-central: Lenga (36°S), Tubul (37°S); south austral: Calbuco (41°S), Castro (42°S), Quellón (43°S). The environmental conditions (i.e. sea surface temperature, precipitation and chlorophyll α) present during each sampling event were also recorded. We evaluated the reproductive parameters of females (fecundity, reproductive output (RO)) as well as their body size (carapace width and dry weight), volume, water content, dry weight, elemental composition (carbon, hydrogen, nitrogen: CHN), and finally the energy content of their embryos. Our results indicated that the environmental conditions of the sea water temperature, precipitation (proxy of water salinity) and chlorophyll α (proxy of food availability) have direct effects on the reproductive parameters of females and the characteristics of their embryos. We observed a low fecundity and high RO in Calbuco and Quellón, where precipitation was high (i.e. diluted salinity) and temperatures and productivity was low. For embryo traits, the highest values of volume and water content were observed in female crabs from the estuarine areas (i.e. Tongoy, Lenga, Tubul), values much higher than those found in the internal sea of Chile (i.e. Calbuco, Castro, Quellón). For the elemental composition, we observed high nitrogen levels and a low C:N proportion in embryos from female crabs from Lenga (a nitrogen enriched area). Fluctuating environmental variables among localities proved to modulate intraspecific variations in females and embryos of H. crenulatus, revealing different reproductive strategies, particularly in the quality and energy investment per embryo, which subsequently influenced successful embryogenesis and larval survival.